So early as the second year of the reign of King Henry IV., Gascoigne was made Chief Justice of the King's Bench, and we find that in 1403 Judge Gascoigne and Ralph Nevill, Earl of Westmoreland, were commissioned by the King to levy and assemble forces in the counties of York and Northumberland in order to quell the insurrection of Henry Percy, Earl of Northumberland. Somewhat later these Commissioners were also empowered to treat with this same rebellious Earl. When Archbishop Scrope and others were taken in arms against the King, His Majesty would have had Gascoigne immediately to give sentence of death against the contumacious Archbishop; but the Chief Justice refused, resolutely declaring he would not pronounce such a sentence in so irregular and illegal a manner. This refusal brought upon him the King's high displeasure, but the people praised him much for his justice and his moderation. Again, when certain abbots, priors, knights, esquires, and other persons of distinction had been wrongfully accused, and were suffering imprisonment in consequence of the evidence of a perjured witness, Sir William detected the fraud. He then caused the false witness to be exposed and condemned, and obtained the release of the guiltless persons. About this time, also, attorneys, by reason of their multitude, and from their malpractices, had grown to be a public nuisance. Chief Justice Gascoigne caused an Act to be passed limiting their number in every county. They had also to swear every Term that they would deal faithfully and truly by their clients, and could it be proved that they had not done so they were liable to be imprisoned for a twelve-month and condemned to pay a ransom according to the King's pleasure. In the abstract of the Parliament rolls there is a lone insertion made of a curious and important case referred in part to the judgment of the Chief Justice. William, Lord Roos of Hamalake, brought an action against Sir Robert Therwit, one of the Justices of the King's Bench, inasmuch as he had withheld certain manors and commons in the county of Lincoln, and that he had lain in wait with five hundred men to seize or apprehend the said Lord. Sir Robert confessed his fault before the King, and offered to abide by the award of two Lords of the complainant's kindred. These two Lords made a long judgment, and amongst other items enjoined that Sir Robert should make a great feast at Milton-le-Roos. That for this feast he should prepare two fat oxen, twelve sheep, two tuns of Gascon wine, and other provisions. That he should then assemble there all such knights, esquires, and yeomen as had been his accomplices. That they should then confess their fault to Lord Roos, craving his pardon, and offering him five hundred marks as compensation. Lord Roos should refuse this sum, but he should pardon them, and partake of their dinner.